Extended Data Fig. 4: Morphological changes in the inner nucellus and germline in mads31.

a, b, Longitudinal sections of wild-type (WT) and mads31 ovules at Ov3 stage. Red asterisks indicate the megaspore mother cell. Scale bars, 25 μm. c, d, Longitudinal sections of WT and mads31 ovules at Ov7/8 stage. Red dashed lines indicate the embryo sac. Black squares are enlarged to highlight differences in the inner nucellus. Scale bars, 50 μm. e, f, Longitudinal sections of WT and mads31 ovules at Ov10 stage. Altered nucellus morphology can be seen in all mutants, including “WT-like” mads31 mutants. Red dashed lines indicate the embryo sac. Yellow arrows indicate cell vacuolation. Black squares are enlargement of the egg apparatus. ANT, antipodal cells; CC, central cell; EA, egg apparatus. Numbers in parentheses in f indicate the number of mutant ovules identified in each category. Scale bars, 50 μm. Representative images were shown from sections of certain number of ovules (in black bracket of a, b, e and f, 3 ovules for c and d).